Volgarr the Viking

Key Stones can only be found on the Path of the Valkyrie. At the end of each World, right before facing the boss, you will see a small garnet shaped object. This is a Key Stone. You will need all five (there is none in World One) to gain access to Yggdrasil’s roots.

Reach the end of World Two on the Path of the Valkyrie and pick up the Key Stone for this achievement.